This invention relates to the display of an image, particularly a digital image, and more particularly, an image of an object, such as a human body, and still more particularly, to display parameter adjustment of digital images of parts of the body. This invention applies to a radiographic apparatus, and more particularly, to mammography.
A mammography apparatus is used for examining the breasts of a patient using X-rays. The image is acquired using means for receiving an image by, for example, a photographic or by means for digital sensing. GE Medical Systems Global Technology Company, LLC, has commercially available a digital mammography under the trade name Sensographe 2000D. The images acquired in this apparatus are displayed on a screen for the operator's attention and inspection. For presenting digital images on the screen, one of the methods employed in this apparatus comprises adjusting contrast and brightness of the image display. For this purpose, a gray level histogram is calculated on the acquired image. Using the calculated histogram, a mean gray level and a gray level range are determined for the display. This determination is done using a look-up table to identify between image gray levels provided by the acquired image and gray scale levels in the displayed image. Adjusting gray levels varies the contrast and brightness of the image displayed on the screen. This method is disclosed in FR 2,786,589.
This apparatus additionally allows part of the image to be magnified on the screen using a soft magnification function. In this case, image contrast and brightness are not modified for displaying the magnified part of the image on the screen.
The operator may be interested in a specific part of the image. This can apply when the soft magnification function is used or again when the operator is using a spot-type compression paddle. The paddle is a device fitted in a ring at one end, allowing compression of a part of the breast to be examined. In this case, the image contrast and brightness are, overall, suited to the complete image but does not allow suitable presentation of the image in the region of interest.